Methyl oeg4 nhsester

Poly-l-lysine hydrobromide (MW =
15–30 kDa by viscosity), poly(sodium 4-styrenesulfonate) (average
MW = 70 kDa), D₂O, and tablets for 10 mM PBS solution (pH
7.4, ionic strength of 150 mM) were obtained from Sigma-Aldrich. HCl
solution was obtained from SelectiPur. Methyl-OEG₄-NHS
ester was purchased from ThermoFisher Scientific, while DBCO-OEG₄-NHS was obtained from Click Chemistry Tools. The membranes
for dialysis (Spectra/Por, 6–8 kDa cutoff, diameter of 6.4
mm) were purchased from Spectrum Labs, Greece. The azide-DNA (MW,
7421 g/mol; 5′-N₃-PEG₄-ACCACAAGTTTATATTCAGTCAT-3′,
23 nt) was acquired from Biomers.net GmbH (chemical structure of the linker in Figure S1). cDNA (complementary to the KRAS sequence, 5′-ATGACTGAATATAAACTTGTGGTAGTTGGAGCTGGTGGCGTAG-3′,
43 nt) and ncDNA (5′-CTACGCCACCTCAACCTACGCCACCTCCACCTACGCCACCTC-3′,
42 nt) were purchased from Eurofins Genomics and used as received.

Poly-l-lysine hydrobromide (MW =
15–30 kDa by viscosity), EDC, NHS, tablets for 10 mM PBS solution
(pH 7.4), 3-trichlorosilylpropyl methacrylate, 2-hydroxyethyl methacrylate
(HEMA), ethylene glycoldimethacrylate (EGDMA), tridecafluoro-(1,1,2,2)-tetrahydrooctyl-trichlorosilane,
bovine serum albumin, ammonium persulfate (APS), and NaCl salt were
purchased from Sigma-Aldrich. Methyl-OEG₄-NHS ester, biotin-OEG₄-NHS ester, Mal-OEG₄-NHS ester, the Zeba spin desalting
columns (7 kDa MWCO, 5 mL), the immobilized TCEP disulfide reducing
gel (tris[2-carboxyethyl] phospine hydrochloride immobilized onto
4%cross-linked beaded agarose), and the streptavidin-Fluorescein conjugate
were obtained from ThermoFisher Scientific. Oligonucleotides were
purchased from Eurofins Genomics and used as received. SiO₂ QCM chips (with fundamental frequency of 5 MHz) were purchased from
Biolin Scientific. Poly(dimethylsiloxane) Sylgard 184 and curing agent
were used as received from Dow Corning. Ormostamp material and MA-T1050
were purchased from Microresist. The PNA probes were synthesized using
the materials and the procedure previously described for PNA₂,^{52 (link)} as briefly reported in the Supporting Information together with the characterization
of the newly synthesized PNA₃ and PNA₄.